It is known to use various cobalt complexes (e.g., cobaloximes or cobalt porphyrins) as chain transfer catalysts (CTC) to provide oligomers or macromonomers bearing terminal double bonds for use in polymeric products. See commonly owned U.S. Pat. Nos. 5,310,807, 5,362,813, 5,412,039, 5,502,113, and 5,587,431 and WO 9525765. All of the polymerizations were initiated with azo initiators commonly employed in the acrylics industry and none of the polymerizations were initiated with hydrogen gas or hydrogen atom donors as described herein.
The use of chain transfer catalysts to control the molecular weight of oligomers and polymers is known. U.S. Pat. Nos. 5,602,220, 5,770,665 and 5,684,101 as well as WO9613527 disclose this control, but do not teach initiation with hydrogen gas or hydrogen atom donors. Commonly owned U.S. Pat. No. 5,726,263, and application Ser. Nos. 08/818,860, 09/193,701 and 08/912,593 also disclose this control, but again, disclose only conventional initiation of polymerization.
The use of chain transfer catalysts in the presence of hydrogen gas to initiate oligomerization and polymerization is disclosed in commonly owned U.S. Pat. No. 4,680,352, but that patent does not teach initiation by hydrogen atom donors. In the disclosure of initiation in the presence of hydrogen gas, the patent cites the use of cobalt complexes with planar macrocyclic rings and particularly bisglyoximato ligands, but does not disclose that certain hydrogen-atom bridged catalysts are far more efficacious than others catalysts.
U.S. Pat. No. 5,306,856 discloses the synthesis of alpha,omega-vinylically-unsaturated oligomers by the high temperature, liquid phase reaction of alpha, omega-diolefin(s) in the presence of aluminium hydrides. The process is not a free radical process, but rather is a coordination polymerization and chain transfer catalysts are not involved.